Effect of Ice Contamination on Liquid-Nitrogen Drops in Film Boiling

Abstract

Leidenfrost film boiling data of discrete masses of a cryogenic fluid were first reported by Keshock and Bell [1,2]. These authors attempted to correlate their cryogenic data using the equations developed by Baumeister et al. [3] from standard laminar film boiling theory. This theory had been found to successfully correlate data for conventional fluids such as water, ethanol, benzene, and carbon tetrachloride. However, Keshock and Bell found the measured drop vaporization times were as much as 30% shorter than predicted by the equations developed by Baumeister et al. [3] even after the contributions of heat transfer by radiation and free convection to the droplet’s upper surface were considered. To account for this discrepancy, the effects of ice contamination and mass transfer from the upper surface of the drop were experimentally investigated in this study. In particular, ice formation in the drop from contamination was found to significantly affect the vaporization times of liquid nitrogen drops.